gistfile1.txt

console.log(`[${process.pid}] ${Date.now()} ${config.file}\tCALL close operation`)
oldObj.close(function (err) {
  console.log(`[${process.pid}] ${Date.now()} ${config.file}\tCOMPLETE close operation`)
  // ... handle err ...
}
console.log(`[${process.pid}] ${Date.now()} ${config.file}\tAFTER CALL close operation`)

gistfile2.txt

[99461] 1490022307339 obj1.bin CALL close operation
[99461] 1490022307340 obj1.bin AFTER CALL close operation
[99461] 1490022307340 obj2.bin CALL close operation
[99461] 1490022307340 obj2.bin AFTER CALL close operation
[99461] 1490022307340 obj3.bin CALL close operation
[99461] 1490022307340 obj3.bin AFTER CALL close operation
[99461] 1490022307340 obj4.bin CALL close operation
[99461] 1490022307340 obj4.bin AFTER CALL close operation
[99461] 1490022307341 obj5.bin CALL close operation
[99461] 1490022307353 obj5.bin AFTER CALL close operation
[99461] 1490022308550 obj1.bin COMPLETE close operation
[99461] 1490022308550 obj2.bin COMPLETE close operation
[99461] 1490022308550 obj3.bin COMPLETE close operation
[99461] 1490022308550 obj4.bin COMPLETE close operation
[99461] 1490022308550 obj5.bin COMPLETE close operation